Role: you are an expert in product ecosystems.

My skills: [skills]
My audience: [audience]

Task: design a product ladder with 4 tiers:
1. low price
2. medium price
3. high-end digital
4. recurring product

Each product should lead naturally into the next one.

For every tier, explain:
- what is being sold
- the price range
- the delivery format
- the type of buyer
- how it leads on to the next product